Easy folding cross brace design

Abstract

First and second U-shaped cross-members each have legs connected by cross bars and pivotally connected with each other at central portions thereof, and are mutually movable from a generally X-shaped setup condition in which the cross bars are transversely spaced apart, to a generally flat collapsed condition. Right and left frame side assemblies respectively are pivotally connected to the first and second cross-members at terminal ends of their respective front and rear portions and by at least one lost motion linkage.

What is claimed is: 
     
       1. An apparatus comprising:
 first and second U-shaped cross-members, each of said cross-members including a front portion, a rear portion, and a cross bar perpendicularly connecting the front portion to the rear portion, wherein the front portions of the first and second cross-members are pivotally connected with each other at central portions thereof and the rear portions of said cross-members are pivotally connected with each other at central portions thereof, and the cross-members are mutually movable from 
 a generally X-shaped setup condition in which the cross bars of the cross-members are transversely spaced apart, to 
 a generally flat collapsed condition in which the front portion and the rear portion of the first cross-member are generally nested within the front portion and the rear portion of the second cross-member; and 
 right and left frame side assemblies respectively pivotally connected to an inside of one of the first and second cross-members at terminal ends of their respective front and rear portions such that the right and left frame side assemblies are at least partially nested within the respective front and rear portions of the first and second cross-members, 
 the right and left frame side assemblies also respectively pivotally connected to the first and second cross-members by at least one lost motion linkage, wherein when the cross-members are moved to their collapsed condition, the right and left frame side assemblies are positioned adjacent one another along their vertical lengths within a generally rectilinear envelope defined by the collapsed first and second cross-members. 
 
     
     
       2. The apparatus as claimed in  claim 1 , wherein each of the cross-members is pivotally connected with the right and left frame side assemblies by first and second links adjacent their respective cross bars, and at least the first link is a slotted link that is at one end pivotally connected to the right frame side assembly and is at the other end pivotally and slidingly connected to the first cross-member. 
     
     
       3. The apparatus as claimed in  claim 1 , wherein when the cross-members are moved to their collapsed condition the right and left frame side assemblies adjacently touch one another along their lengths within the generally rectilinear envelope defined by the collapsed cross-members. 
     
     
       4. The apparatus as claimed in  claim 1 , further comprising back support members, which are movable from upright positions generally perpendicular to the cross bars of the cross-members when the cross-members are in their setup condition, to folded positions generally aligned with the cross-members in their collapsed condition. 
     
     
       5. The apparatus as claimed in  claim 4 , wherein the back support members in their upright positions are attached directly at the right and left frame side assemblies, and in their folded positions are removed from the right and left frame side assemblies. 
     
     
       6. The apparatus as claimed in  claim 4 , wherein the back support members in their upright positions are generally perpendicular to the lateral portions of the frame side assemblies, and in their folded positions are generally aligned with the lateral portions of the frame side assemblies. 
     
     
       7. The apparatus as claimed in  claim 4 , further comprising a back support panel that is stretched across the back support members when the cross-members are in their setup position and is flaccid when the cross-members are in their collapsed condition. 
     
     
       8. The apparatus as claimed in  claim 4 , wherein the back support members in their upright positions are attached into respective sockets of the frame side assemblies, and when removed from the sockets to their folded positions are attached to the frame side assemblies via the flaccid back support panel. 
     
     
       9. The apparatus as claimed in  claim 1 , further comprising a seat panel attached at the cross bars of the cross-members, which is taut across the cross bars in the setup condition of the cross-members, and is flaccid in the collapsed condition of the cross-members. 
     
     
       10. The apparatus as claimed in  claim 1 , further comprising a handle attached to one of the cross-members. 
     
     
       11. The apparatus as claimed in  claim 1 , further comprising a tray pivotally attached by an over-center linkage to one of the frame side assemblies. 
     
     
       12. The apparatus as claimed in  claim 11 , wherein in the collapsed condition of the cross-members, the tray is nested into the one of the frame side assemblies to which it is pivotally attached. 
     
     
       13. The apparatus as claimed in  claim 1 , further comprising a snubber attached at one of the frame side assemblies for frictionally locking at least one of the cross-members into its setup condition. 
     
     
       14. An apparatus comprising:
 first and second U-shaped cross-members, each of said cross-members including a front portion, a rear portion, and a cross bar perpendicularly connecting the front portion to the rear portion, wherein the front portions of the first and second cross-members are pivotally connected with each other at central portions thereof and the rear portions of said cross-members are pivotally connected with each other at central portions thereof, the cross bar of the second cross-member is longer than the cross bar of the first cross-member so that the front and rear portions of the second cross-member extend forward and rearward of the front and rear portions of the first cross-member respectively, and the cross-members are mutually movable from 
 a generally X-shaped setup condition in which the cross bars of the cross-members are transversely spaced apart, to 
 a generally flat collapsed condition in which the front portion and the rear portion of the first cross-member are generally nested within the front portion and the rear portion of the second cross-member; 
 a seat panel attached to the cross bars of the first and second cross-members, said seat panel being taut in the setup condition of the cross-members and flaccid in the collapsed condition of the cross-members; 
 right and left frame side assemblies respectively pivotally connected to an inside of one of the first and second cross-members at terminal ends of their respective front and rear portions such that the right and left frame side assemblies are at least partially nested within the respective front and rear portions of the cross-members, 
 the right and left frame side assemblies also respectively pivotally connected to the first and second cross-members by at least one lost motion linkage; 
 right and left back support members respectively attached to the right and left frame side assemblies; and 
 a back panel attached to the back support members. 
 
     
     
       15. The apparatus as claimed in  claim 14 , wherein when the cross-members are moved to their collapsed condition, the right and left frame side assemblies and the back support members are positioned adjacent one another along their vertical lengths and nested within a generally rectilinear envelope defined by the collapsed cross-members. 
     
     
       16. The apparatus as claimed in  claim 14 , wherein the back support members are movable from upright positions generally perpendicular to the cross bars of the cross-members, to collapsed positions generally parallel to the cross bars of the cross-members. 
     
     
       17. The apparatus as claimed in  claim 14 , wherein the back support members are removable from the right and left frame side assemblies and are attached to the seat panel by the back panel. 
     
     
       18. The apparatus as claimed in  claim 14 , wherein each of the right and left frame side assemblies respectively is pivotally connected to the first and second cross-members by first and second links, and at least the first link is a slotted link that is at one end pivotally connected to the right frame side assembly and is at the other end pivotally and slidingly connected to the first cross-member. 
     
     
       19. A plurality of apparatuses stackable in side-by-side arrangement, each said apparatus comprising:
 first and second U-shaped cross-members, each of said cross-members including a front portion, a rear portion, and a cross bar perpendicularly connecting the front portion to the rear portion, wherein the front portions of said cross-members are pivotally connected with each other at central portions thereof, and the rear portions of said cross-members are pivotally connected with each other at central portions thereof, the cross bar of the second cross-member is longer than the cross bar of the first cross-member so that the front and rear portions of the second cross-member extend forward and rearward of the front and rear portions of the first cross-member, respectively, and the cross-members are mutually movable from 
 a generally X-shaped setup condition in which the cross bars of the cross-members are transversely spaced apart from one another, to 
 a generally flat collapsed condition in which the front portion and the rear portion of the first cross-member are generally nested within the front portion and the rear portion of the second cross-member; and 
 right and left frame side assemblies respectively pivotally connected to an inside of one of the first and second cross-members at terminal ends of their respective front and rear portions such that the right and left frame side assemblies are at least partially nested within the respective front and rear portions of the cross-members, 
 the right and left frame side assemblies also respectively pivotally connected to the first and second cross-members by at least one lost motion linkage, 
 wherein when the cross-members are moved to their collapsed condition, the right and left frame side assemblies are nested within a generally rectilinear envelope defined by the collapsed cross-members.